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Randall C
Randall C, ASE Master Tech
Category: Chevy
Satisfied Customers: 12835
Experience:  ASE Master, L1, 32 years, Diagnostic / Electrical Specialist
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2004 Tahoe 4WD...oil pressure gauge pegged high on way back

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2004 Tahoe 4WD...oil pressure gauge pegged high on way back from long trip(500 miles each way...AC on..75-85 mph...air temp 95). Oil changed 100 miles prior to trip..oil looks good and within normal range..engine temp. normal too. Engine also now seems sluggish...original plugs in with 125,000 miles...due for tune up. Concerned about the high oil pressure reading, and whether sudden sluggishness is related.
Hello, Can you tell me what size engine you have? thanks
Customer: replied 8 years ago.
Yeah..sorry... it's the 5.3 liter

Unlike old style oil pressure senders and guages, the oil pressure switch in this vehicle is a 'data" sensor 3 wire that feeds a special signal to the PCM ( Powertrain control module) The PCM then converts signal to send info for guage. There really should not be any direct relationship between oil pressure and Sluggish running but... as noted below, if you are developing a class BUS communication problem , yes, another circuit could be affected thus maybe having a bearing on an engine control. This is something you should have scanned soon. Not just for codes but full scan to test BUS communication. Although you say your guage goes high, I would still request a oil pressure test. High oil pressure is as bad as low as seals could start blowing out causing a big problem.


Description and Operation


The IPC displays the engine oil pressure as determined by the PCM. The IPC receives a class 2 message from the PCM indicating the engine oil pressure. The engine oil pressure gage defaults to 0 kPa (0 psi) or below if:

  • The PCM detects a malfunction in the engine oil pressure sensor circuit.
  • The IPC detects a loss of class 2 communications with the PCM.


Customer: replied 8 years ago.
so the high oil gauge reading could be simply a relay issue like a sending unit type module problem, or is there any specific engine malfunction that could trigger it?

It could be one of several problems thus why it should be checked manualy.

Sender, PCM, BUS communication, guage, or internal problem like a regulator valve inside engine and an oil filter has been known to cause this as well. I would get manual reading to ruel out internal problem

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